The last time the US had a president who was a war hero the country's foreign relations underwent something of a renaissance. During John F Kennedy's term in office there was a détente with Germany and a stand-off with the Soviet Union, both of which helped to put the cold war on hold. On the other hand, Cuba was mishandled and the effects were long lasting, but on the whole the US presented a reasonably attractive face to the world during the Camelot years.

Now another battle-scarred warrior is making a tilt at the White House and this week we might get a clearer idea of John McCain's world vision when he fetches up in Europe and the Middle East to look at the lie of the land and chew the fat with its leaders.

There's no doubting the man's courage or his fortitude. Shot down over North Vietnam he endured a torrid five years in prison in Hanoi where he was beaten regularly - he still can't hold his arms above his head - and refused any special treatment. As the son of the US commander-in-chief in the Pacific, he could have been shipped out of Hanoi but he refused all offers unless other prisoners-of-war were included in the deal.

That makes him a pretty tough cookie - I've seen the cell in which he was kept and even in its sanitised state the experience was clearly no picnic - but will he transfer that sense of resolve into his foreign policy? The short answer is yes.

While he has voiced reservations about the way the war in Iraq was handled, he favours a hard line. Instead of withdrawing troops from the country as the Democrats favour, McCain wants to increase the size of the garrison by 100,000. Their presence, he argues, will guarantee the success of last year's surge and it's no surprise that he's a great fan of General David Petraeus. How that goes down with the ordinary soldier is another matter - last week McCain forecast that the problems in Iraq might take 100 years to solve.

The same goes for Afghanistan, where he believes that the West is in for the long haul and must see it through until the Afghans learn to be responsible for their own internal affairs. McCain is 71 and probably won't live to see either country emerge from the shadows but that doesn't stop him wanting to play the long game.

Like most Americans, he would like to see the Europeans playing a bigger role but he's not a critic of "Old Europe", far from it. He has supported the notion of enlargement both for Nato and the European Union and, unlike the neocons of the Bush era, he is not afraid to be seen in public with leaders such as Angela Merkel and Nicolas Sarkozy. He's also gone on record as saying that he wants a close working relationship with Kremlin new boy Dmitry Medvedev and, unlike Hillary Clinton and Barack Obama, he actually knows the new Russian president's name.

It's not all hard lines and war games. In common with anyone who has been involved at the sharp end of war McCain is no gung-ho glory-hunter. He has seen what happens when people are brutalised by violence and his philosophy embraces an optimism that war can be stopped if people combine in common cause.

One of his great daydreams is the creation of a League of Democracies, a kind of global club that would work to reduce international tensions and find solutions to eternal problems - the suffering in Darfur, the prevalence of Aids/HIV in most of Africa and the worrying re-emergence of malaria south of the Sahara.

It sounds idealistic and it is. It also sounds mighty like the sort of thing the United Nations should be doing and that's because McCain is no great supporter of the organisation and in an ideal world would like to bypass it with his League of Democracies.

Clearly McCain is a man with strong and decided views and it will be interesting to see how he handles his first overseas tour now that he has secured the right to run for the White House as the Republican's choice.

His aides say that he will be listening and doing little talking but that's not the full measure of the man. Not everyone warms to his firm approach to international affairs but at least it is possible to read him and get some idea of where he is coming from.

A former colleague from his navy days put him in a nutshell when he said that everything McCain did was guided by the primary need to protect the liberty of the individual. After all, he knows what it is like when it is taken away.